Safety cap assembly for pressurized founts of gasoline burning devices



Feb. 7, 1967 w. H. PLAMANN 3,302,664

SAFETY CAP ASSEMBLY FOR PRESSURIZED FOUNTS OF GASOLINE BURNING ICESFiled April 7, 1

W a W United States Patent 3,302,664 SAFETY CAP ASSEMBLY FOR PRESSURIZEDFOUNTS 0F GASOLINE BURNING DEVICES William H. Plamann, Wichita, Kans.,assignor to The Coleman Company, Inc., Wichita, Kans., a corporation ofKansas Filed Apr. 7, 1964, Ser. No. 358,016 3 Claims. (Cl. 138-89) Thisinvention relates to a safety cap assembly for pressurized founts ofgasoline burning devices. The safety cap assembly has particular utilityfor use with the founts or reservoir tanks of portable gasoline burningdevices, such as gasoline lanterns, gasoline stoves, etc.

Such gasoline burning devices are provided with gasoline storage tanksor founts, which are an integral part of the complete lantern or stove,and which therefore are located in close proximity to the gasolineburning element, such as the stove burner or the illumination burner. Itis necessary, of course, to provide a filler inlet in the top of upperportions of the founts, which inlet is equipped with a removable cap topermit the founts to be refilled with gasoline as required. Since theoperation of the devices requires that the founts be pressurized, a handpump being provided for creating the required pressure within thefounts, the removal of the closure caps may involve a sudden release ofpressure as the cap is unscrewed. This pressure release may cause thegasoline in the fount to froth or foam, and either liquid gasoline orgasoline froth may blow out and be ejected with the outward movement ofair in the release of the fount pressure.

It is, therefore, a general object of the present invention to provide asafety cap assembly for pressurized founts of gasoline burning deviceswhich overcomes the problems described above, while at the same timebeing simple and economical to manufacture and which performssatisfactorily under repeated use. More specifically, it is an object toprovide a safety cap assembly of a type described which positivelydirects the released air and gasoline away from the burner element ofthe stove or lantern, and which therefore provides for a safe opening ofthe filler inlet even if the burner element is at a relatively hightemperature or is still ignited. Other objects and advantages will beindicated in the following detailed specification.

This invention is shown in an illustrative embodiment in theaccompanying drawing, wherein FIGURE 1 is an elevational view of a.gasoline lantern equipped with a pressurizedfount and a filler inlet ofa kind with which the present invention is particularly applicable; 7

FIG. 2 is an enlarged fragmentary side elevational view of the fount ofthe lantern in FIG. 1, showing the safety cap assembly as it wouldappear in place during the normal operation of the lantern;

FIG. 3 is an enlarged detail view, partly in section, of the safety capassembly;

FIG. 4 is a transverse sectional view of the safety cap assembly takenon line 44 of FIG. 3;

FIG. 5 is a bottom view of the cap and gasket members of the assembly;and

FIG. 6 is an enlarged fragmentary sectional view illustrating the methodof functioning of the pressure release means of this invention.

In FIG. 1 of the drawings, there is shown a gasoline lantern 10 having agasoline tank or fount 11 which is equipped with the usual hand pump 12for creating pressure within the fount. Fount 11 is provided with asafety cap assembly constructed in accordance with the presentinvention, the assembly being designated generally by the 3,382,664Patented Feb. 7, 1967 ice number 13. It will be understood, however,that the safety cap assembly of this invention is adapted for use inconjunction with other gasoline burning devices having pressurizedfounts, including particularly gasoline-burning camp stoves.

As shown more clearly in FIGS. 2 and 3, the safety cap assembly includesa filler bushing or sleeve 14 having a lower portion 15 adapted forattachment to the fount 11, and an externally threaded upper portion 16.In the illustration given, lower end 15 of the bushing is provided withan annular shoulder 16 which facilitates the uniting of the bushing tothe fount through a ring of copper braze 17. It will be understood thatother methods of attachment can be employed, such as Welding.

A closure cap 18 provided with internal threads 19 is received on thethreaded upper end 16 of the bushing 14. The bushing threads 20 are inthreaded engagement with the cap threads 19, as shown more clearly inFIGS. 3 and 6.

The cap assembly is provided with gasket means mounted within the cap 13for establishing sealing engagement with the upper end of the bushing.In the illustration given, there is provided a gasket ring 21 which isheld ina recess of a gasket carrier 22. To permit cap 13 to be rotatedindependently of gasket 21 and carrier 22, the carrier is supported bymeans of a retainer screw 23. This arrangement tends to minimizefrictional wear on the gasket during the final stages of tightening thecap or the initial stages of removing the cap. The bottom face of thegasket 21 can thereby be engaged and disengaged with the outer end 24 ofthe bushing without a relative scrubbing action between the parts. Thisconstrnction in itself is not new, and in fact is well known in the art,and it is not believed it will be necessary to further describe itherein.

As already indicated, this invention is particularly concerned with ameans of achieving a safe release of the fount pressure when the cap 13is unscrewed. Consequently, in accordance with the present invention,one of the engaging threaded portions of the bushing 14 and the cap 18is provided with a plurality of circumferentially spaced,axially-aligned channels extending across the zone of threadedengagement between these parts. For achieving the results of the presentinvention, these channels are designed to provide open paths ofcommunication between the exterior atmosphere at the bottom of the capand the interior of the cap adjacent the level of sealing engagementbetween the bushing end 24 and the gasket 21. As shown in'FIGS. 3 and 6,the bushing end 24 and the gasket 21 seal at a level outwardly of thezone of threaded engagement between the bushing threads 20 and the capthreads 19.

Bushing threads 26 may advantageously be provided in a band area whichis adjacent the outer end 24 of the bushing but spaced inwardlytherefrom. As shown in FIGS. 3 and 6, this construction provides anannuular space 25 immediately adjoining the lower face of gasket 21 andthe upper end 24 of the bushing. As indicated in FIG. 6, a separation ofthe gasket 21 from the bushing end 24 brings the annular space 25 intocommunication with the interior of the fount through the passageprovided by the bushing 16. Thus, the pressurized air together withliquid gasoline or gasoline froth will first enter the annular space 25after it passes between gasket 21 and bushing end 24 as these parts areseparated in the unscrewing of the cap. Since space 21 extends entirelyaround the inside of the cap, the fluid under pressure can distributeitself around the circumference of the cap within the passage 25. Themeans for safely venting the pressurized fluid from the annular passage25 will now be described.

In the illustration given, the inside of cap 18 is provided with aplurality of channels 26. The channels are axially aligned and extendupwardly from the lower end of cap 18 to a level adjacent the level ofsealing engagement between the gasket 21 and the bushing end 24. Asshown more clearly in FIGS. 3 and 6, the inner ends of the channels 26communicate directly with the annular pressure relief space 25.Preferably, more than one of the channels 26 are provided incommunication with the annular space 25, and the channels 26 may becircumferentially spaced around the inside of the cap. In theillustration given, four of the channels 26 are provided, and areequally spaced around the interior of the cap, as shown more clearly inFIGS. 4 and 5. In order that the pressure relief passages provided bythe channels 26 are in open communication with the annular space 25 andthe exterior atmosphere, the channels have a greater depth than thethreads 19 across which the channels extend. More specifically, thebottoms of the channels 26 are outwardly of the root depth of thethreads 19, as shown particularly in FIGURES 3 and 6.

In the manufacture of the caps 18, the channels 26 may be advantageouslyformed by a broaching operation prior to the cutting of the threads 19.Formation of the channels after threading might damage the threads. Ifdesired, the channels 26 may extend upwardly further than shown in thedrawings, although this would usually be unnecessary where the annularpassage 25 is employed adjacent the inner ends of the channels.

There is an advantage in forming the pressure relief channels in thecap, especially where the cap is formed of a softer metal, such asbrass, while the bushing is formed on a harder metal, such as steel.Where the member providing the channels is formed of a softer metal thanthe other member, there is much less tendency for the channels to act asthread chasers with resulting damage to the threads of the other member.It will be understood that the cap 18 may be formed of other relativelysoft metals, such as aluminum or copper, While providing the sameadvantages. Alternatively, the bushing 14 may be formed of a relativelysoft metal, such as brass, aluminum, copper, etc., while the cap 18 isformed of a relatively harder metal, such as steel. Where the bushing isformed of a softer metal than the cap, the broached channels should beformed in the bushing while the threads in the cap will beuninterrupted.

To facilitate gripping of the cap 18 with the fingers, it can beprovided around its outside with a knurled surface 27.

Operation The operation of the safety cap assembly of this invention isillustrated particularly in FIGS. 3 and 6. In FIG- URE 3, the capassembly is shown in closed position with the gasket 21 in sealingengagement with the upper end 24 of the bushing. In this condition, thegasoline in fount 11 will normally be under pressure as produced by thepump 12. As cap 18 is unscrewed by manually gripping the knurled surface27, the gasket 21 will separate from the bushing end 24 with a breakingof the sealing engagement therebetween. The pressurized air from withinthe fount, together with any entrained liquid gasoline or gasolinefroth, with then flow into the annular space 20, as indicated in FIG. 6,and from there outwardly through the channels 26. Since these channelsare directed downwardly toward the upper surface of the fount 11, theentrained gasoline or gasoline foam is safely discharged, and is keptaway from and out of contact with the burner element of the heatingdevice. As will be noted, the direction of discharge is not dependent onthe position of the cap 18 as it is being unscrewed. After the pressurehas thus been safely released, the cap 18 can then be unscrewed the restof the way and removed from the bushing 14.

While this invention has been described in the foregoing specificationin relation to a specific embodiment thereof, it will be apparent tothose skilled in the art that hte invention is susceptible to otherembodiments without departing from the basic principles of theinvention, and that many of the details described herein can be variedconsiderably while still achieving the objects of this invention.

I claim:

1. In a safety cap assembly, including a filler bushing having a lowerportion for attachment to a pressurized fount of a gasoline burningdevice and an externally threaded upper portion, an internally threadedclosure cap received on said bushing upper end portion in threadedengagement therewith, and gasket means mounted within said cap forestablishing sealing engagement with the upper end of said bushing at alevel outwardly of the zone of threaded engagement between said cap andbushing, the means for achieving a safe release of the fount pressurewhen said cap is unscrewed characterized by said cap being provided witha plurality of circumferentially spaced, axially aligned channelsextending inwardly from the lower end thereof to the level of saidsealing engagement, said cap being formed of a substantially softermetal than said bushing, said channels having a greater depth than theroot depth of the threads in said cap, and providing open paths ofcommunication for both liquid and vapor between the exterior atmosphereat the bottom of said cap and said level of sealing engagement adjacentsaid gasket.

2. The safety cap assembly of claim 1 wherein said cap is formed ofbrass and said bushing is formed of steel.

3. The safety cap assembly of claim 1 characterized further in that thethreads on said bushing terminate at a spaced distance from the upperend thereof, and an annular space is provided around the outer endportion of said gasket, the upper portions of said channelscommunicating with said annular space.

References Cited by the Examiner UNITED STATES PATENTS 1,022,211 4/1912Thomas 22()-29 1,228,285 5/1917 Bieker 220--29 1,649,587 11/1927 Halaby220--44 2,202,185 5/ 1940 Broecker. 2,990,079 6/1961 Garvey 215-56THERON E. CONDON, Primary Examiner.

JAMES R. GARRETT, Examiner.

1. IN A SAFETY CAP ASSEMBLY, INCLUDING A FILLER BUSHING HAVING A LOWERPORTION FOR ATTACHMENT TO A PRESSURIZED FOUNT OF A GASOLINE BURNINGDEVICE AND AN EXTERNALLY THREADED UPPER PORTION, AN INTERNALLY THREADEDCLOSURE CAP RECEIVED ON SAID BUSHING UPPER END PORTION IN THREADEDENGAGEMENT THEREWITH, AND GASKET MEANS MOUNTED WITHIN SAID CAP FORESTABLISHING SEALING ENGAGEMENT WITH THE UPPER END OF SAID BUSHING AT ALEVEL OUTWARDLY OF THE ZONE OF THREADED ENGAGEMENT BETWEEN SAID CAP ANDBUSHING, THE MEANS FOR ACHIEVING A SAFE RELEASE OF THE FOUNT PRESSUREWHEN SAID CAP IS UNSCREWED CHARACTERIZED BY SAID CAP BEING PROVIDED WITHA PLURALITY OF CIRCUMFERENTIALLY SPACED, AXIALLY ALIGNED CHANNELSEXTENDING INWARDLY FROM THE LOWER END THEREOF TO THE LEVEL OF SAIDSEALING ENGAGEMENT, SAID CAP BEING FORMED OF A SUBSTANTIALLY SOFTERMETAL THAN SAID BUSHING, SAID CHANNELS HAVING A GREATER DEPTH THAN THEROOT DEPTH OF THE THREADS IN SAID CAP, AND PROVIDING OPEN PATHS OFCOMMUNICATION FOR BOTH LIQUID AND VAPOR BETWEEN THE EXTERIOR ATMOSPHEREAT THE BOTTOM OF SAID CAP AND SAID LEVEL OF SEALING ENGAGEMENT ADJACENTSAID GASKET.